package orderpackage;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;

@Entity
public class PurchaseOrder {
   @Id
   @GeneratedValue(strategy=GenerationType.AUTO)
   private int id;
   
   @OneToMany(mappedBy="order",cascade=CascadeType.ALL)
   private Set <OrderLine> orderLine = new HashSet<OrderLine>();
   
   public PurchaseOrder(String orderName) {
      this.orderName = orderName;
   }

   public Set<OrderLine> getOrderLine() {
      return orderLine;
   }

   public void setOrderLine(Set<OrderLine> orderLine) {
      this.orderLine = orderLine;
   }

   private String orderName;

   public int getId() {
      return id;
   }

   public void setId(int id) {
      this.id = id;
   }

   public String getOrderName() {
      return orderName;
   }

   public void setOrderName(String orderName) {
      this.orderName = orderName;
   }
   

}

package orderpackage;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;

@Entity
public class OrderLine {
   
   
   private int id;
   private String itemName;
   private int qty;
   
   
   private PurchaseOrder order;
   
   
   public OrderLine(String itemName, int qty) {
      this.itemName = itemName;
      this.qty = qty;
   }
   
   @ManyToOne(fetch=FetchType.LAZY,cascade=CascadeType.ALL)
   @JoinColumn(name="ORDER_ID")
   public PurchaseOrder getOrder() {
      return order;
   }
   public void setOrder(PurchaseOrder order) {
      this.order = order;
   }
   
   @Id
   @GeneratedValue(strategy=GenerationType.AUTO)
   public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }
   public String getItemName() {
      return itemName;
   }
   public void setItemName(String itemName) {
      this.itemName = itemName;
   }
   public int getQty() {
      return qty;
   }
   public void setQty(int qty) {
      this.qty = qty;
   }
   
   

}

package orderpackage;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class OrderTest {
   
   public static void main(String[] args) {
      
   PurchaseOrder order = new PurchaseOrder("order no 1");
   OrderLine orderLine1 = new OrderLine("item1",25);
   OrderLine orderLine2 = new OrderLine("item2",28);
   OrderLine orderLine3 = new OrderLine("item3",38);
   OrderLine orderLine4 = new OrderLine("item4",48);
         
   order.getOrderLine().add(orderLine1);
   order.getOrderLine().add(orderLine2);
   order.getOrderLine().add(orderLine3);
   order.getOrderLine().add(orderLine4);
         
   SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
   Session session = sessionFactory.openSession();
   
   session.beginTransaction();
   session.persist(order);
   session.getTransaction().commit();
   session.close();
   }

}

ibernate: select hibernate_sequence.nextval from dual
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: insert into PurchaseOrder (orderName, id) values (?, ?)
Hibernate: insert into OrderLine (itemName, ORDER_ID, qty, id) values (?, ?, ?, ?)
Hibernate: insert into OrderLine (itemName, ORDER_ID, qty, id) values (?, ?, ?, ?)
Hibernate: insert into OrderLine (itemName, ORDER_ID, qty, id) values (?, ?, ?, ?)
Hibernate: insert into OrderLine (itemName, ORDER_ID, qty, id) values (?, ?, ?, ?)